Aircraft wheel support mechanism

ABSTRACT

An aircraft wheel support mechanism capable of reducing the impact to the tire at the time of landing and capable of reducing the impact to the tire at the time of the wheel colliding with an obstacle lying on the runway. The mechanism comprises a suspension mechanism ( 3 ) for rotatably supporting a wheel ( 13 ) by the lower end of a support member ( 2 ) connected to the fuselage, the suspension mechanism ( 3 ) having a crank shaft assembly ( 5 ), and is characterized in that the crank shaft assembly comprises a horizontal support shaft ( 51 ) rotatably supported by the lower end of the support member, an axle ( 52 ) for rotatably supporting the wheel, and an arm ( 53 ) positioned at right angles with the horizontal support shaft and axle for connecting one end of the horizontal support shaft to one end of the axle.

FIELD OF THE INVENTION

[0001] The present invention relates to a support mechanism forsupporting a wheel in an aircraft.

BACKGROUND OF THE INVENTION

[0002] In recent years, as shown in FIG. 9, the support mechanism for awheel in an aircraft has a structure in which kinetic energy of afuselage 1, caused by a descending speed at the time of landing, isabsorbed by using a buffer mechanism 11 for buffering longitudinalmovements, such as an oleo-type buffer device. With this structure, animpact force Fg generated on a runway 12 is weakened to Fb andtransmitted to the fuselage 1.

SUMMARY OF THE INVENTION

[0003] (Technical Problems to be Solved by the Invention)

[0004] With respect to the aircraft, the velocity of approach to arunway sometimes reaches about 300 km/hour at the time of landing, and agreat impact in the horizontal direction is imposed on tires of wheels13 at the time of landing. This impact is referred to as acceleratingimpact in dynamical terms. For this reason, as shown in FIG. 9, uponlanding, the surface of a tire of a wheel 13 sometimes melts to raisesmoke 14. The molten tire material 15 adheres onto the runway 12.

[0005] The tire material 15 adhered onto the runway 12 results indegradation in safe aircraft operations. In other words, the followingproblems are raised.

[0006] (1) When it gets wet by rain or the like, the tire material 15causes slipping of wheels of an aircraft that passes thereon.

[0007] (2) The runway 12 sometimes needs to be closed so as to removethe tire material 15 therefrom, and the operation schedule becomestighter due to the closed runway 12.

[0008] Moreover, the molten tire surface tends to cause a flat tire. Theflat tire directly impairs the safe aircraft operations. In the event ofa flat tire, the runway needs to be temporarily closed, making theoperation schedule tighter to cause the subsequent degradation in safeaircraft operations.

[0009] Furthermore, recently, a tragic big aircraft accident occurred inwhich a supersonic aircraft caught a fire upon landing and crashed. Itis considered that the cause of this accident was that wheels of theultrasonic aircraft collide with a metal piece lying on the runway at ahigh speed to cause a tire to burst and a broken part to smash into afuel tank or an engine. For this reason, there have been strong demandsfor mechanisms which can prevent a tire from bursting even when itcollides with an obstacle on the runway.

[0010] The objective of the present invention is to provide an aircraftwheel support mechanism which can alleviate an impact imposed on thetire at the time of landing, and also alleviate an impact imposed on thetire even when the tire collides with an obstacle lying on the runway.

[0011] (Means to Solve the Problems)

[0012] In accordance with a first aspect of the present invention whichrelates to a support mechanism for supporting wheels in an aircraft, thesupport mechanism is provided with a suspension mechanism for rotatablysupporting a wheel by the lower end of a support member connected to thefuselage, and the suspension mechanism has a crank shaft assembly, andin this arrangement, the crank shaft assembly includes a horizontalsupport shaft rotatably supported by the lower end of the supportmember, an axle for rotatably supporting the wheel, and an armpositioned at right angles with the horizontal support shaft and axlefor connecting one end of the horizontal support shaft to one end of theaxle.

[0013] In accordance with a second aspect of the present invention thatrelates to the invention of the first aspect, the suspension mechanismis provided with a control means that controls rotation operations ofthe horizontal support shaft.

[0014] In accordance with a third aspect of the present invention thatrelates to the invention of the second aspect, before landing, thecontrol means rotates the horizontal support shaft to shift the axleperpendicularly below the horizontal support shaft so that thehorizontal support shaft is clamped in this state with the crank shaftassembly standing still, and immediately before landing the clampedstate is released.

[0015] In accordance with a fourth aspect of the present invention thatrelates to the invention of the first aspect, a braking mechanism, whichcarries out a braking operation on the wheel, is prepared, and thebraking mechanism carries out the braking operation by pressing abraking face of the wheel with a braking member, and in thisarrangement, the braking member is connected to the support memberthrough a link mechanism, and the link mechanism is arranged to maintaina parallel positional relationship with the crank shaft assembly.

[0016] (Effects Superior to the Prior Art)

[0017] In accordance with the first aspect of the present invention,upon landing, the crank shaft assembly is activated so that the wheelstarts to rotate around the axle while being subjected to an angularshift upward in the rear direction around the horizontal support shaftso that, during the angular shift, the weight of the fuselage is notdirectly imposed on the wheels. Therefore, during the angular shift,that is, during the operation of the crank shaft assembly, it ispossible to effectively suppress the tire of the wheel from generatingsmoke. Moreover, when the axle is positioned perpendicularly above thehorizontal support shaft to finish the angular shift, the weight of thefuselage is directly imposed on the wheel; however, at this time, sincethe wheel has already been made in contact with the runway to rotatethereon, the quantity of slipping of the corresponding wheel at thistime is small. Therefore, it is possible to prevent the tire frommelting at this time. In other words, in accordance with the inventionof the first aspect, it is possible to prevent the tire of the wheelfrom melting upon landing, and consequently to prevent the molten tirematerial from adhering to the runway, as well as preventing occurrenceof a flat tire due to worn tire. Thus, it becomes possible to improvethe safety in the aircraft operations.

[0018] Moreover, even when a wheel collides with an obstacle lying onthe runway while running thereon, the crank shaft assembly is activatedso that the wheel is subjected to an angular shift and released rearwardaround the horizontal support shaft; thus, it becomes possible toalleviate an impact to be imposed on the wheel. Therefore, it becomespossible to prevent the tire from bursting even when the wheel collideswith an obstacle upon running on the runway, and consequently to improvethe safety in the aircraft operations from this point of view also.

[0019] In accordance with the second aspect of the present invention,during the operations of the crank shaft assembly, the control meansimposes a load on the rotation of the horizontal support shaft so thatit becomes possible to prevent the crank shaft assembly from excessivelyvibrating centered on the horizontal support shaft upon running on therunway. Therefore, a stable running operation on the runway isavailable.

[0020] In accordance with the third aspect of the present invention, thecrank shaft assembly can be clamped by the control means before landingso that it becomes possible to prevent the crank shaft assembly fromvibrating due to strong wind. This ensures stable flight before landing.

[0021] In accordance with the fourth aspect of the present invention,even when the crank shaft assembly is activated to subject the wheel toan angular shift around the horizontal support shaft, the brakingmechanism is always allowed to carry out braking operations normally.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1, which is a perspective view that indicates an aircraftwheel support mechanism of the present invention, shows a state beforelanding.

[0023]FIG. 2, which is a perspective view that indicates the aircraftwheel support mechanism of the present invention, shows a state afterlanding.

[0024]FIG. 3 is a longitudinal cross-sectional view that shows thesupport mechanism in the state shown in FIG. 1.

[0025]FIG. 4 is an exploded perspective view that shows the aircraftwheel support mechanism of the present invention.

[0026]FIG. 5 is a side view that continuously shows landing operationsof the aircraft wheel support mechanism of the present invention.

[0027]FIG. 6 is a perspective view that shows a normal state of theaircraft wheel support mechanism upon running on the runway.

[0028]FIG. 7 is a perspective view that shows a state in which theaircraft wheel support mechanism collides with an obstacle upon runningon the runway.

[0029]FIG. 8 is a schematic view that shows a modified example of acrank shaft assembly.

[0030]FIG. 9 is a side view that continuously shows landing operationsof a conventional aircraft wheel support mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031]FIGS. 1 and 2 are perspective views that indicate an aircraftwheel support mechanism of the present invention, and FIG. 1 shows astate before landing and FIG. 2 shows a state after landing. FIG. 3 is alongitudinal cross-sectional view that shows the support mechanism inthe state shown in FIG. 1. FIG. 4 is an exploded perspective view thatshows the support mechanism.

[0032] The support mechanism of the present invention is provided with asuspension mechanism 3 and a braking mechanism 4 at the lower end of asupport member 2. The suspension mechanism 3 has a crank shaft assembly5 and a control means 6.

[0033] The support member 2 extends downward from the lower portion of afuselage (not shown). The support member 2 incorporates a buffermechanism for buffering longitudinal movements, that is, for example, anoleo-type buffer device 21. The oleo-type buffer device 21 is aconventionally known device. As shown in FIG. 3, the oleo-type bufferdevice 21 has an arrangement in which an elastic force is exerted by acoil spring 211 when it is extended or compressed, while a damping forceis exerted when its sealed oil 212 is allowed to pass through an orifice213.

[0034] The crank shaft assembly 5 of the suspension mechanism 3 isprovided with a horizontal support shaft 51 that is rotatably supportedby the lower end of the support member 2 through a rolling bearing 31,an axle 52 that rotatably supports a wheel 13 through the rollingbearing 31 and an arm 53 that connects one end of the horizontal supportshaft 51 to one end of the axle 52. The arm 53 is positioned at rightangles with the horizontal support shaft 51 and axle 52. The horizontalsupport shaft 51 and the axle 52 are located on the side opposite to thearm 53. In FIG. 3, a roller bearing is used as the rolling bearing 31,and a ball bearing is used as the rolling bearing 32.

[0035] The control means 6 is comprised of a torque generator 61 and acontrol unit 62 (FIG. 4). With respect to the torque generator 61, forexample, a motor, a dynamo-electric generator or the like may be used.The torque generator 61 controls the rotary torque and rotation angle ofthe horizontal support shaft 51. The control unit 62 controls operationsof the torque generator 61. Moreover, a transmission (not shown) isplaced between the torque generator 61 and the horizontal support shaft51.

[0036] The braking mechanism 4 is provided with a disc brake 41 thatcarries out a braking operation on the wheel 13 by sandwiching a brakingrotor (braking face) with pads (braking members). The pads are held in acaliper that is built in a bracket 411. The bracket 411, which isrotatably supported by the axle 52 through the rolling bearing 33, isconnected to a protruding portion 22 of the supporting member 2 througha link mechanism 42. The link mechanism 42 has an arrangement in whichone end of a link 421 is rotatably connected to the protruding portion22 through a pin 423, while the other end of the link 421 is rotatablyconnected to the top end of an extending portion 412 of the bracket 411through a pin 422 so as to maintain a parallel positional relationshipwith the crank shaft assembly 5. Here, as shown in FIG. 4, the linkmechanism 42 is comprised of two sets of the link 421 and the pins 422and 423.

[0037] As shown in FIGS. 1 through 4, the support member 2 is formed byconnecting an upper tube 23 and a bottom tube 24. Reference numeral 25represents a strut rotation-stopping arm.

[0038] The following description will discuss operations of the supportmechanism having the above-mentioned arrangement.

[0039] Before landing, a signal is sent from the control unit 62 to thetorque generator 61 so that the rotation of the horizontal support shaft51 is controlled by the torque generator 61; thus, the crank shaftassembly 5 is set to an orientation in which the axle 52 is placedperpendicularly below the horizontal support shaft 51, that is, a stateas shown in FIG. 1, so that the crank shaft assembly 5 is subjected to abraking force applied to the horizontal support shaft 51, and clamped inthis state.

[0040] Next, the control unit 62 determines the state immediately beforelanding based upon a signal from an altitude sensor. Immediately beforelanding a signal is sent from the control unit 62 to the torquegenerator 61 so that the braking operation by the torque generator 61 isreleased, thereby the clamped state of the crank shaft assembly 5 isreleased.

[0041] As shown in FIG. 5, the fuselage 1 is then allowed to startlanding. Upon landing, the support mechanism having the above-mentionedarrangement carries out the following operations.

[0042]FIG. 5(a) shows the support mechanism immediately before thelanding. Here, during flight, the wheel 13 is housed inside the fuselage1 in a state shown in FIG. 2. As shown in FIG. 5(b), when the wheel 13is made in contact with the runway 12 at point A, an impact force fa isgenerated in the rear direction. As shown in FIGS. 5(b) to 5(f), thewheel 13 starts rotating around the axle 52 through this impact force,while it is allowed to pivot around the horizontal supporting shaft 51to start an angular shift upward in the rear direction so that theangular shift is made up to 180 degrees. During this period, the weightof the fuselage 1 is not directly applied onto the wheel 13. Thefrictional quantity of work W exerted by the wheel 13 while it is inslipping-contact with the runway 12 is represented by the productbetween the amount of slipping contact S and the load M to be applied tothe wheel 13. That is, W=S×M. Consequently, since, during the angularshift, the weight of the fuselage 1 is not directly applied to the wheel13, the load M is extremely small. Therefore, since the frictionalquantity of work W is maintained at a very small value, the tire 131 ofthe wheel 13 hardly generates smoke.

[0043] When the wheel 13 has made an angular shift by 180 degrees aroundthe horizontal supporting shaft 51, the oleo-type buffer device 21 isactivated so that, as shown in FIGS. 5(f) to 5(i), the descending energyof the fuselage 1 is absorbed by the buffer device 21; thus, the impactforce fg is weakened to fb, and transmitted to the fuselage 1. At thistime, the load of the fuselage 1 is directly applied onto the wheel 13;however, since the wheel 13 has already been made in contact with therunway 12 to rotate thereon, the impact in the rear direction is hardlyapplied to the wheel 13. Consequently, the tire 131 of the wheel 13hardly generates smoke during these operations. Additionally, the strokeof the buffer device 21 is stopped by oil locking.

[0044] After landing, the wheel 13 is allowed to run along the runway 12in a state shown by FIG. 5(i), that is, in a state shown in FIG. 2.During the running operation, when there is an obstacle lying on therunway 12, the support mechanism having the above-mentioned arrangementcarries out the following operations.

[0045] As shown in FIG. 6, in the case when the wheel 13 is running inthe state as shown in FIG. 2 with a protrusion 121 lying on the runway12, upon running on to the protrusion 121, the wheel 13 is allowed tomake an angular shift around the horizontal support shaft 51 as shown inFIG. 7, and released in the rear direction as indicated by arrow A.Thus, an impact applied to the wheel 13 from the front direction isreleased in the rear direction and alleviated. Moreover, since the wheel13 is released in the rear direction to make the duration time of theimpact to the wheel 13 longer, the instantaneous impact force becomesweaker. Therefore, even when, upon running on the runway, the wheel 13collides with an obstacle, the impact applied to the wheel 13 becomessmaller so that it is possible to prevent the tire 131 from bursting.

[0046] Moreover, when the wheel 13 makes an angular shift around thehorizontal support shaft 51, the link mechanism 42 of the brakingmechanism 4 is operated in the following manner.

[0047] In FIG. 2, the link mechanism 42 is allowed to maintain aparallel positional relationship with the crank shaft assembly 5;therefore, when the wheel 13 makes an angular shift around thehorizontal support shaft 51, the link mechanism 42 is operated whilemaintaining the parallel positional relationship with the operations ofthe crank shaft assembly 5. When, as shown in FIG. 2, the crank shaftassembly 5 is shifted to a position at which the axle 52 is locatedperpendicularly above the horizontal support shaft 51, the linkmechanism 42 is shifted to a position at which the pin 423 is locatedperpendicularly above the pin 422. Therefore., even when the wheel 13makes an angular shift around the horizontal support shaft 51, the discbrake 41 of the braking mechanism 4 is always maintained in a state thatallows normal operations.

[0048] In the supporting mechanism having the above-mentionedarrangement, the following effects are obtained:

[0049] (1) Since the wheel 13 is supported by the suspension mechanism 3having the crank shaft assembly 5 at the lower end of the support member2 and since, upon landing, the crank shaft assembly 5 is operated asshown in FIG. 5, it becomes possible to effectively prevent the tire 131of the wheel 13 from generating smoke.

[0050] (2) Even in the case when, upon running, the wheel 13 collideswith an obstacle (protrusion 121) on the runway 12, the crank shaftassembly 5 is operated as shown in FIG. 7, it becomes possible toalleviate an impact onto the wheel 13, and consequently to prevent thetire 131 from bursting.

[0051] (3) Since the control means 6, which controls the rotationoperation of the horizontal support shaft 51, can apply a load onto therotation of the horizontal support shaft 51 during the angular shift andrunning of the wheel 13, it is possible to prevent the crank shaftassembly 5 from vibrating centered on the horizontal support shaft 51.

[0052] (4) Since, before landing, the crank shaft assembly 5 is clampedby the control means 6 in a state as shown in FIG. 1, it is possible toprevent the crank shaft assembly 5 from vibrating due to strong wind.

[0053] (5) The link mechanism 42 is arranged so as to maintain aparallel positional relationship with the crank shaft assembly 5;therefore, even when the shaft 13 makes an angular shift around thehorizontal support shaft 51, it is possible to always maintain the discbrake 41 of the braking mechanism 4 in a normal operable state.

[0054] (6) Since a transmission is installed between the torquegenerator 61 and the horizontal support shaft 51, the torque to beapplied to the horizontal support shaft 51 is increased by thetransmission. Therefore, it becomes possible to make the torquegenerator 61 smaller and light-weight.

[0055] (7) In the case when the crank shaft assembly 5 is manufacturedby using carbon fibers, it becomes possible to make the crank shaftassembly 5 lighter and also to increase the impact alleviating functionof the crank shaft assembly 5.

[0056] Additionally, the crank shaft assembly 5 having theabove-mentioned arrangement has a schematic structure as shown in FIG.8(a), and may have a structure as shown in FIG. 8(b) or 8(c). In FIG.8(b), axles 52 are located on both sides of the horizontal support shaft51 through an arm 53. In FIG. 8(c), horizontal support shafts 51 arelocated on both sides of the axle 52.

Reference Numeral of Drawings

[0057]1 . . . Fuselage

[0058]1 3 . . . Wheel

[0059]2 . . . Support member

[0060]2 1 . . . Oleo-type buffer device

[0061]3 . . . Suspension mechanism

[0062]4 . . . Braking mechanism

[0063]4 1 . . . Disc brake

[0064]4 2 . . . Link mechanism

[0065]5 . . . Crank shaft assembly

[0066]5 1 . . . Horizontal support shaft

[0067]5 2 . . . Axle

[0068]5 3 . . . Arm

[0069]6 . . . Control means

[0070]6 1 . . . Torque generator

[0071]6 2 . . . Control unit

What is claimed is:
 1. An aircraft wheel support mechanism comprising: a suspension mechanism (3) for rotatably supporting a wheel (13) by the lower end of a support member (2) connected to a fuselage, wherein: the suspension mechanism has a crank shaft assembly (5), and the crank shaft assembly comprises a horizontal support shaft (51) that is rotatably supported by the lower end of the support member, an axle (52) for rotatably supporting the wheel, and an arm (53) positioned at right angles with the horizontal support shaft and axle for connecting one end of the horizontal support shaft to one end of the axle.
 2. The aircraft wheel support mechanism according to claim 1, wherein the suspension mechanism comprises a control means (6) that controls rotation operations of the horizontal support shaft.
 3. The aircraft wheel support mechanism according to claim 2, wherein: before landing, the control means rotates the horizontal support shaft to shift the axle perpendicularly below the horizontal support shaft so that the horizontal support shaft is clamped in this state with the crank shaft assembly standing still, and immediately before landing the clamped state is released.
 4. The aircraft wheel support mechanism according to claim 1, further comprising: a braking mechanism (4) that carries out a braking operation on the wheel, wherein: the braking mechanism carries out the braking operation by pressing a braking face of the wheel with a braking member, and the braking member is connected to the support member through a link mechanism (42) and the link mechanism is arranged to maintain a parallel positional relationship with the crank shaft assembly. 